Connecting the Oxidative Potential of Fractionated Particulate Matter With Chromophoric Substances. Issue 4 (16th February 2022)

• Record Type: Journal Article
• Authors: Wu, Na; Lu, Bingqing; Chen, Qingcai; Chen, Jianmin; Li, Xiang
• Is Part Of: Journal of geophysical research. Volume 127:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-16
• Subjects: oxidative potential (OP) -- dithiothreitol (DTT) assay -- excitation‐emission matrix (EEM) -- chromophores -- parallel factor analysis (PARAFAC); Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2021JD035503
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Particulate matter (PM) air pollution is recognized as a major cause of adverse health outcomes, yet much remains unknown about which fractions and compositions are the most harmful. Efforts in this direction can be improved by employing a cell‐free approach, dithiothreitol (DTT) assay, the so‐called oxidative potential (OP). Here, we provide a detailed examination of OP from fractionated PM by a combination extraction method of solvent and solid‐phase extractions (SPE). We estimate that the average OP of water‐soluble matter (WSM; 4.27 nmol/min/m 3 ) is up to 1.2 times higher than methanol‐soluble matter (3.66 nmol/min/m 3 ) in most seasons apart from summer. Of these WSM, OP is distributed almost equally between hydrophobic and hydrophilic fractions. OP of PM is mainly related to transition metals (Cu: 12.1%, Mn: 2.5%); apart from these, more than 80% of the total OP remains unidentified. Identification of this unexplained OP by a novel approach, integrating the chromophore characteristics with parallel factor analysis, has shown that chromophore1 (C1) accounted for 98% of OP, although this factor only made a small contribution to the total fluorescence. Our paper highlights the importance of a holistic approach by evaluating the chemical structure‐activity relationship between optical characteristics and OP. Information presented here draws a connection between light‐absorbing organic aerosols and a possible toxicological mechanism on the basis of their optical properties. Abstract :